If a black wire of platinum is heated, its colour first appears red, then yellow, and finally white. This can be understood on the basis of:

The intensity of radiation emitted by the sun has its maximum value at a wavelength of $510\;nm$ and that emitted by the north star has the maximum value at $350\;nm$. If these stars behave like black bodies,then the ratio of the surface temperature of the sun and north star is

The wavelength of maximum energy,released during an atomic explosion,was $2.93 \times 10^{-10} \ m$. Given that the Wien's constant is $2.93 \times 10^{-3} \ m \ K$,the maximum temperature attained must be of the order of

For a perfectly black body,a graph is plotted between the frequency of radiation with maximum intensity $(v_m)$ and the absolute temperature $T$. Which of the following graphs is correct?

If the temperature of a black body is doubled,the frequency at which the spectral intensity becomes maximum will be

The maximum wavelength of radiation emitted by a star is $289.8 \ nm$. The intensity of radiation for the star is (Given: Stefan's constant $\sigma = 5.67 \times 10^{-8} \ W \ m^{-2} \ K^{-4}$,Wien's constant $b = 2898 \ \mu m \ K$)